Exposure to electromagnetic fields can cause interference or damage to electrical equipment, causing that equipment to malfunction or rendering it nonoperational. For example, electrical equipment and electronics can be destroyed, or otherwise fail in the event of a strong electromagnetic pulse or intentional electromagnetic interference event (EMP/IEMI).
EMP/IEMI events typically take one of two forms. First, high field events correspond to short-duration, high voltage events (e.g., up to and exceeding 100 kilovolts per meter), and typically are of the form of short pulses of narrow-band or distributed signals (e.g., in the frequency range of 14 kHz to 10 GHz). These types of events typically generate high voltage differences in equipment, leading to high induced currents and burnout of electrical components. Second, low field events (e.g., events in the range of 0.01 to 10 volts per meter) are indications of changing electromagnetic environments below the high field damaging environments, but still of interest in certain applications.
Existing systems are used to adjust to a narrow range of threats, and thus systems developed to address a certain problem are not useful to address other problems necessitating electromagnetic shielding that are exposed during use of other electronic equipment. One such unaddressed concern is for example equipment related to surveillance, such as video and infrared cameras. Typically, video camera lenses require exposure to an external environment to provide a field of view for that camera to capture. In circumstances where reliable operation through possibly damaging events is desirable, such as in the case of security cameras or sensitive image capture equipment, there is currently no reliable way to ensure such operation in the case of exposure of the camera to possible damage due to EMP/IEMI events.
For these and other reasons, improvements are desirable.